Humidity regulator



` comparti?, INoonroRArEn, or Nnw Yonx, N.l Y.,=a ooaronurroN oii Naw-ronda# Patented May 2), 1924.

uNiTsofsrArEs PATENT or -JoixN JonNs'roN, or NEW HAVEN, coNNEc'rroU'n- Assroivonzro wssrmNnEcmo Homin REGULATOR.

Application led December 10, 1921. Serial Ko. 521,313.4

To all 'whoml it may concern:-

liey it known that I, JOHN JOHNSTON, a citizen of the United States, residing at New .Haven, in the county of ANew Haven, State of Connecticut, have invented certain new and useful Improvements in Humidit Regulators, of which the following is a full, clear, concise, and exact description.

An object of the invention is to provide moisture contained in an enclosed area`or s ace may beheld at a constant value alt ough moisture is continuously being transordinarily corresponds to ,approximately 7-5 ferred from or to the airin said space and whereby the content of water in an aque-r ous solution, which is subject to change in concentration, maybe kept within narrow limits. The drawing illustrates this invention as applied to preventing loss of water from storage battery solutions.

' In storage battery units such as those eint plo ed in telephone central oliices, consideraiile difficulty has been experienced in maintaining the solutions contained in the batteries at the desired concentration. There are three factors involved, which should be taken into consideration in the operation of a storage battery:

1. The loss of water from the battery solution caused by evaporation.

2. The loss of water caused by the electrolytic decomposition thereof.

3. The pro ssive dilution of the battery solution on discharging, and a grop'ortional increase in concentration on c erging, resulting from the removal or addition of sulphate ions at the negative electrode.

Thron h the operation of the proposed means, wiich form the basis of the Eresent invention the concentration of the attery solution or a 'ven condition of charge or discharge, may maintained within any desired limits.

The drawing shows a saturated salt solution 1, such as a saturated solution of sodium chloride, preferably having a large eirposed surface, contained in avessel 2. This maybe suspended from the ceiling of the battery room or placed in any other desired location. Within or beneath this vessel, heating means 3, equip ed with a thermostat f1 may be placed. o circulate the air This invention relates to humidity regii- -lators. i

' air to 'escapeftherefroin over the vsurface 0f the saturated "solution,

an electric fan 5 may be' .placed at 'some int near the solution, `pijei'erably`-lextendl To ventilato the rom an opening' 9i Inria i be blows b the ai, 5j diiec'uyreyer tiiescflii#V tion; 'In t is case, there sh ing 10 `in the walls .o f t sodium chloride gives a vapor Rressnm-;

waterlostby ittlir ugh eyaporatioii., be made in such a psitioiithatirtheai. wi l 05 ouldbe 'an open- -l *he The vapor pressure' of 7 ricci-if which corresponds to about jper contest-+75' uraton.. If itis desired, therefera to prevent loss' of water through-vaporizationt4 from the battery solution,.or to compensates for loss of water through-the decompositionthereof, the thermostata -should belse'tgsolo that the relative humidity of the airnearthefi.-

surface of the battery solutionfwillbe withinv` the limits set as desirable for the' normal vapor pressure of the battery' solution. To.,

accomplish this, it will be necessaryforfthe? saturated salt solution 'tohave avapor pres# sure suicently above that of the batterysolution vto overcome the v`resistance of ther. air between the two solutions'. In order to partially overcome this air resistance, the an 5 may be set in motion tolcirculate the water va or from the salt'solution about the room. y suiiciently increasing the rate of circulation of the air in the room, this air resistance can be reduced almost to zero. 95

The'thermostat 4 may be set to raise the temperature of the saturated salt solution so as to give it the required constantvapor pressure. In settin must be te en into consderat0n;;namely, the decrease or increase in the concentration of the battery solution caused by the loss oi sulphate ions on discharging, and their addition on charging; and the` corresipondng.105;` increase or decrease, respectively, in vom.

pressure of the battery solution. t charging or discharging process. is going in one direction or the other most of the time, 1t

will ordinarily be sucient to regulate the llo I the thermostat, the-third factor l the choice o .temperature of the saturated salt solution so ticularly described in connection. with sta` such as used in tele hone 1t may be applied to t e ordinary ortable storage batteries by placing about tiie cell a solution saturated with a suitable salt to givethe desired vapor pressure. i t

A saturated solution has been specified, as it is apparent that such a solution 1s the most convenient to use since its vapor pressure is unchanged by loss of water" through eva oration. It 1s obvious, however, that if t e cycle of changes through which the water must pass, i; e., from the salt solutionto the tiona batteries, centra offices,

air and from the air to the battery solution, is 'determined by experiment, the salt solution may be kelpt at any concentration, which will produce t e required effect.

While a solution of sodium chloride has been specified, because if its cheapness, as a desirable salt of any other' salt may be used for the purposes of this invention, provided that it'has a proper` vapor pressure.

a salt whose solution has the 'In any given case saturated aqueous vapor pressure appro nate .-to the particular-condition, will enab e the thermostatto be dispensed with.

One of the advantages of this invention is the fact that no supply of distilled water nor any apparatus for producing it need be maintained. The water ilowing"into the saturated'salt solution may be ordinary tap water, for, as Ait is converted into vapor before its introduction into the battery solution, it is thereby automatically freed from any impurities which would be harmful to the battery.

In some cases it might be desirable to al- 192 low evaporation ofwater from' the battery cellt'o take place, but on account of the prestity of the und-issolved'salt mi of the air in the room.

to use, anaqueous solution ywith the st rage ence of .other apparatus in the battery room, Ait might be necessary to provide means to prevent the condensation ofmoisture 'u on such apparatus. In order 'to accomp sh this, it is necessary to maintain a salt solu tion at a vapor pressure low] enough to prevent condensationof water in any. part of the roon.` In this case,4 a considerable quanht be kept in thorou h contact with lthe so ution Ato prevent d1 ution thereof. I

I While the inventionha's been described as" applicable particularly to storage batteries,

it 1s evident that the 'the resent invention vmay beextended-to inprinciple underlying clu e cases where the battery is replaced b areservoirv of aparticular solution which 1s subject to loss or a 'rption of water; and the maintenance solution with'a constant vapor afford a means-.for Aregulating' t ressure will The invention claimed is:

1. The method of preventin'g'loss of water from storage batterysolutions, which con' sists in maintaining in -an enclosed'space batteries an a 'ueous-'solution saturated with' a soluble sa t and having at a given temperature a 'slightly higher vapor pressure than that of the attery so1u' tion.

the concentration of an which consists in prov1d1ng 1n anenclosed space therewith a'second aqueous solution,

Withinithe room of a salt e humidity 2. Theme thod of maintaining constant aqueous. solution;

and. in maintaining the second solution at a predetermined temperature and degree of concentration. L

3. In combination a battery cell, an electrol te contained therein, and means for maintaining constant the concentration of the electrolyte.

In witness whereof,

my name this 8th day of December A.' D.,

4 JOHN Jonn'sroifr.

I hereunto subscribe l 

